Android: allows using adb from a chromium checkout without envsetup.sh

There are situations like running tests where it's not necessary to run envsetup.sh.
However, build/android/pylib requires adb to be in the path.
Rather than requiring envsetup, it can be smart enough to set the path itself.

BUG=242960

Review URL: https://chromiumcodereview.appspot.com/15891002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@202558 0039d316-1c4b-4281-b951-d872f2087c98

build/android/pylib/__init__.py

@@ -2,3 +2,18 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+import os
+import subprocess
+
+
+if not os.environ.get('ANDROID_SDK_ROOT'):
+  # If envsetup.sh hasn't been sourced and there's no adb in the path,
+  # set it here.
+  with file(os.devnull, 'w') as devnull:
+    ret = subprocess.call(['which', 'adb'], stdout=devnull, stderr=devnull)
+    if ret:
+      print 'No adb found in $PATH, fallback to checked in binary.'
+      os.environ['PATH'] += os.pathsep + os.path.abspath(os.path.join(
+          os.path.dirname(__file__),
+          '..', '..', '..',
+          'third_party', 'android_tools', 'sdk', 'platform-tools'))